Tuesday, March 31, 2009


This is obviously my second time around for the shaping and glassing of the float, so I have just a few pictures and comments.

In the last post I forgot to mention that I had constructed the second bow slightly different. I made the central core of four sheets at the same time. But on the second bow I attached the outer pieces with contact cement, like Ian suggested. On the first one I had used QF (thinking, 'how could contact cement be strong enough?'), which worked and shaped easily, but the contact cement is lighter and was easier to construct. There was no tendency for the pieces to slip in the garbage bag vacuum clamp. I think it takes longer to cure to the same strength, but it held up great while shaping. As they say, listen to the designer.

Free-hand shaping with an electric hand planner is quick and more controllable than you would first think. You can see the desired profile penciled along the stem. Final shaping was with the longboard.

A small hand router with a guided trim bit cuts off the excess deck along the hull. After this I longboarded the upper hull to make sure I was happy with its shape since it will serve as final guide for the next step.

A 45-degree bit with roller guide starts the deck radius. This is quick and makes hand sanding faster and easier to control. I used the same radius sander made from PVC pipe to make most of the edge, but my final radius does change along the length of the boat and is finished with the longboard.

I think I learned on the first float to fair the foam more aggressively. Three-eights foam seems thin to be thinking of sanding too much, but it's the high spots that make the low spots, which will need filling. The risk seems to be that the surface can flex, specifically between the bulkheads, with only the interior layer of glass. Hence the possibility of taking off more over the bulkheads -- while in between, the material flexes away instead of being sanded off. Theoretical or real, I'm not sure.

Finished shape.

I glassed in my usual fashion without any incidents. (Both pictures with plastic still on.) I'm not sure I've mentioned it, but somewhere along the way I've started blowing off the surface with compressed air. Even after vacuuming several times it makes an enormous difference, though it does foul the air for a while.

The skirt of painter's plastic allows me work out the excess resin and not worry about messing the floor, etc. From my experience last time, I would say that the extra effort of rebating the foam for extra layers of glass is well worth it.

Trying to go another step in removing bubbles that develop while mixing the QF, I 'worked' the QF before putting it in the bag used to make my stripes. It helped, but at the cost of a smaller time window to apply. I'm not convinced I'll always do this.

The instructions say to apply multiple thin coats so you can minimize the bubbles. Of course I'm trying to avoid the multiple applications, and in particular the stripes are not 'worked' after applying. Would putting the material in a brief vacuum reduce them? In the end, fixing the few that are apparent after sanding is not really that big of a deal.

I advance guides forward to help keep them straight and the proper distance for my trowel. Quick and easy, but the real value is how this helps in later stages.

This was the real test for rigid vs. flexible longboarding. I went after the surface with the rigid board, then checked it with all my straight edge tricks. **SUCCESS!** Fast, easy, and 100% fair! None of the fiddle from before. I would strongly endorse using a rigid board.

'Working' the material seems to remove the bubbles. A 45ยบ action decreases the chance of getting air trapped along the stripe. A word of caution – it doesn't take long for the QF to become 'dry' in how it behaves with the laminate. What I mean is that it is still workable, but if you spread it out and then remove it to examine the surface, it will not have as wet an appearance as it does when spread just after mixing. I again recommend reading Wayne Hick's treatise, part of which I will quote:

"The most frustrating part is getting the micro to spread out evenly without it tearing, lifting up, or rolling up into a ball behind the trowel. The trick is to go slow enough to give the micro time to spread out from under the trowel and stick to the surface. You'll notice that the micro doesn't want to stick at first, but give it a few seconds. The epoxy within the dry micro will migrate outward and will wet out the surface. Once this happens, the micro will adhere and will spread out easier. (This is why some builders like the epoxy wipe.)"

So, I guess by his description, I'm suggesting that the epoxy 'migration' decreases the closer you get to gel, and may happen while it still seems to be spreadable. I think his material has a much longer work time.

((DISCLAIMER: My guess is that all builders will experiment with different techniques, and likely come to different conclusions. Experience, materials, tools, personality, and goals will influence choices. The value in reading each other's experience is not to find a recipe, but to have a multitude of potential approaches and 'tricks' to springboard from (or things to avoid). This became very evident when I bought a new batch of QuickFair. I'm not sure what the reason was, but it had slight, but important differences in how it handled. For a while I felt like I was learning all over. Each builder will likely have slightly different experiences and draw different conclusions about how they want to approach similar problems -- by sharing them we all win. My own techniques are a first time builder learning from reading and doing. They will evolve as I push forward, and this commentary is on my experience and choices – which are not to be construed as the right or better way.))

I'm still marking the top of the stripes so that I can spot-sand any areas where the trowel may have floated high, as you can see here.

A reminder why the stripes have to be left high – they're the first to come off when the real fun begins.

Three long evenings after work: stripes, fair and fill, then fair. Looks like I'll make it with a single application/sand, though I won't know till later, as we leave on a trip tomorrow.

My wife and I took a trip to see our daughter in California. While last fall I drove straight down, then explored the Sierras on my way home, this time we worked our way down, then flew home and let my parents drive the rig back up the coast several weeks later.

We crossed to the central Oregon coast (reliving part of our honeymoon, this just happens to be our 24th wedding anniversary).

Then we drove diagonally across northern California. The west coast has a string of volcanoes – here is Mt. Shasta.

My goal was to see Yosemite again, this time in the spring with all the snow melt. So different than the fall! Water everywhere.

Yosemite Falls with Merced River.

Breakfast under El Capitan.

Rainbows at every falls.

Evening glow from Tunnel View, Bridal Veil Falls.

Breakfast looking across Cook Meadow. In the morning, Yosemite Creek was frozen slush, and we could hear loud crashes as large chunks of ice were carried over the falls. Above the 3000+ foot cliffs is nothing but snow and ice. Tioga Pass, which I drove last fall just before it closed, will not usually open till late May.

Hike to Upper Yosemite Falls with Half Dome in distance.

We crossed California yet again to drive the coast. The foot hills down to the San Joaquin Valley were full of poppies and red bud.

Walking against a strong wind at a beach along Big Sur.

One of the few mainland sea lion colonies. Mamas and young, but no bulls at this time of year.

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